Manufacture of zinc sulfid



PAUL COMMENT, OF MULHOUSE, FRANCE.

MANUFACTURE OF ZINC SULFID.

No Drawing.

To all whom it may concern:

Be it known that I, PAUL COMMENT, a citizen ofthe Republic ofSwitzerland, residing in Mulhouse, Alsace, France, have invented certainnew and useful Improvements in the Manufacture of Zinc Sulfid,.of whichthe following is a specification.

In the invention described in the main application No. 167618, dated the9th May, 1917, the preparation of anhydrous sulfid of zinc is carriedout b means of anhydrous zinc persulfid, by cal cination of the latterwith anhydrous zinc sulfate, in the presence of an alkali-metal sulfate.

The present invention is for the purpose of extending the process to theapplication, in the preparation of anhydrous zinc sulfid, of polysulfidsof zinc having the same action as ersulfid.

be following example will enable the nature and scope of the presentinvention to be clearly understood. 7

Instead of persulfid of zinc,-oorresponding to the formula ZnS theinvention may also be carried out by employing any polysulfid of zinc,such for example as is obtained, with or without an admixture of zincsulfid, by precipitating salts of zinc by means of varying quantities ofalkali-metal or alkali-earthmetal polysulfids, or by any other means.

This w1ll in particular'be the case when the quantity of alkali-metal oralkali-earthmetal polysulfid is insuflicient to form exactly ZnS or whenby other means, and with a view to decreasin the quantity of sulfurousacid produced uring calcination,

the zinc pentasulfid has for example been treated by means of alkalinelyes or solutions of alkali-metal or aAkali-earth-metal sulfids for thepurpose of eliminating therefrom a more or less considerable part of thesulfur, combined or free.

The polysulfid ZnS in which n can vary from 1 to 5, is prepared bydouble reaction between a solution of an alkali-metal (or alkali-earthmetal) polysulfid and a solut1on of chlorid of zinc, using thetheoretical proportions,

MS being capable of being Na s Na s aS BaS Bas etc).

Specification of Letters Patent.

Patented Apr. 12, 1921.

Application filed April 23, 1919. Serial No. 292,096.

The precipitated polysulfid of zinc, filtermg well, is washed, dried,mixed with anhydrous sulfate of zinc, with or without anhydrous sodiumsulfate, and then calcined, protected from the air, at a temperaturebetween 500 and 800.

Theoretical portions of zinc polysulfid and mm sulfate are used with theaddition of one molecular proportion of sodium sulfate,

if desired.

Ewample. 2ZnSO ZnS =3ZnS+4SO (N a 80,) (N a SO utilizing for 322 kilosof anhydrous sulfate of zinc, 228 kilos of polysulfid and 142 kilos vfid' of zinc, stable against atmospheric agents and applicable inpainting, comprising calcining a mixture comprising a polysulfid of zincother than the persulfid and sulfate of zmc.

3. A process for preparing anhydrous sulfid of zinc, stable againstatmospheric agents and applicable in painting, comprising calcining amixture comprising a polysulfid of zinc other than the persulfid, analkali-metal sulfate, and a salt of zinc comprising an oxygenatedcompound of sulfur.

4. A process for preparing anhydrous sulfid of zinc, stable againstatmospheric agents and applicablein painting, comprism calcining amixture comprisin a polysul d of zinc other than the persulfi analkali-metal sulfate and sulfate of zinc.

In Witness whereof I have hereunto signed my name.

PAUL COMMENT.

